000 WTPZ42 KNHC 040846 TCDEP2 HURRICANE BLANCA DISCUSSION NUMBER 15 NWS NATIONAL HURRICANE CENTER MIAMI FL EP022015 400 AM CDT THU JUN 04 2015 The small eye of Blanca has become less distinct in infrared satellite images since yesterday afternoon. Subjective and objective Dvorak T-numbers have subsequently decreased from their peak, so the initial intensity has been lowered to 110 kt. It is not clear whether the slight decrease in wind speed is a result of an eyewall replacement cycle, drier air wrapping into the circulation, or upwelling of cooler waters beneath the nearly stationary hurricane. In any case, as the cyclone begins moving northwestward, low vertical wind shear and warmer water, along the forecast path of Blanca, favor strengthening during the next day or so. The new NHC intensity forecast is close to the SHIPS guidance, but shows a slightly lower peak intensity than the previous few advisories. After 48 hours, increasing shear and cool waters should induce weakening. A faster rate of weakening is expected after 72 hours, when the hurricane is forecast to move over SSTs below 26 deg C and into a drier and more stable air mass. Blanca has remained nearly stationary during the past few hours. The model guidance is in good agreement that the hurricane will begin to move northwestward today while a mid-level ridge builds over northern Mexico. Blanca should move northwestward to north- northwestward at a faster forward speed during the next few days between the aforementioned ridge and a mid-level trough extending southwestward from southern California. The track guidance is tightly clustered, but there are still significant differences in the forward speed of the hurricane. As a result, the NHC track remains close to the model consensus, between the faster GFS, and the slower ECMWF model. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 11.9N 104.9W 110 KT 125 MPH 12H 04/1800Z 12.6N 105.6W 115 KT 130 MPH 24H 05/0600Z 13.9N 106.7W 120 KT 140 MPH 36H 05/1800Z 15.2N 107.9W 125 KT 145 MPH 48H 06/0600Z 16.7N 109.1W 120 KT 140 MPH 72H 07/0600Z 19.3N 110.5W 90 KT 105 MPH 96H 08/0600Z 22.5N 111.5W 50 KT 60 MPH 120H 09/0600Z 25.0N 113.0W 30 KT 35 MPH $$ Forecaster Brown